---
name: mstar-sdd
description: "Morning Star subagent-driven development (SDD) — file handoff, per-task implementer + task reviewer (L2), progress ledger, branch review-package for plan QC tri (L3). **Implementer session** `fresh` (default) or **`sticky`** (same dev subagent across tasks — `references/sticky-implementer-session.md`). **Must** Read when project-manager runs `Execution mode: sdd` (multi-task plan, single-plan, or iteration Phase 2), dispatches SDD implementer/reviewer subagents, or prepares review-package paths. Leaf implementer/reviewer subagents skip PM sections via SUBAGENT-STOP in dispatch prompts."
---

## Load order

**Before first Read:** `mstar-harness-core` → `mstar-dispatch-gates`. Path symbols → **`mstar-conventions`** (`{SDD_DIR}`). Plan QC after SDD → **`mstar-review-qc`**. On conflict, **`mstar-harness-core` wins**.

<SUBAGENT-STOP>
If you were dispatched as an SDD implementer or task reviewer, skip PM orchestration sections. Follow your dispatch prompt only.
</SUBAGENT-STOP>

## When to use

- Plan locked; tasks mostly independent; PM orchestrates in-session
- Assignment has **`Execution mode: sdd`**
- **Not** for hotfix inline work (`Execution mode: inline`) or leaf self-dispatch

## Core principle

**Default:** fresh implementer per ready task + task-scoped review + plan QC on the changed diff and directly affected interfaces. Execution scope → **`mstar-harness-core`** § 定向执行与验证边界.

**Optional:** **`SDD implementer session: sticky`** — same implementer subagent across sequential tasks on one plan/branch; **task reviewers stay fresh per task**. SSOT → **`references/sticky-implementer-session.md`**.

> **Engine check (when available):** import `implementerSessionStickyRules` from `@mstar-harness/engine` in a host hook to validate the sticky resume decision above (no CLI form yet). On `fail` -> do not proceed; fix and re-run. Skill text below remains authoritative when the runtime is absent.

**Narration:** at most one short line between tool calls — ledger and file paths carry the record.

**Continuous execution:** do not check in with the human between tasks. Stop only for BLOCKED, genuine ambiguity, or all tasks complete.

## Pre-flight plan scan

Before Task 1, scan plan once for:

- tasks contradicting Global Constraints
- plan-mandated items that review rubric would flag as defects

Batch all findings for the human in one message. If clean, proceed silently.

## Ready-task scheduling (PM only · Decision Rules)

Dispatch independent ready tasks concurrently after L2 worktree isolation. Keep one canonical per-plan `{SDD_DIR}`. PM alone writes its `context.json`, `progress.md` and workflow snapshot; prepare context-dependent helper outputs serially. Each writable track has its own worktree/branch and immutable task-specific absolute brief/report/diff paths. Artifact subdirectories are namespaces inside that SDD root, never a second SDD root. Parallel leaves use the supplied paths directly and do not invoke shared-context helpers or read mutable context to choose their checkout; never share a writable session or `implementer-session.json`. Use **fresh** implementers for parallel tasks. Serialize only actual dependencies, overlapping write ownership, one sticky session, and integration merges; state the dependency when serializing. A task reviewer may run alongside an unrelated ready implementer. PM alone reconciles reports into the shared `progress.md` and workflow snapshot.

**Rescheduling checkpoint:** a running background task is never a reason to stop scheduling. Re-run this ready-task check at the Phase-2 checkpoints named in **`mstar-iteration/references/phase-2-worktree-lease.md` §2.4** — that file is the single authoritative home for the five checkpoint names and their reason vocabulary, and they are deliberately not re-listed here — and start every authorized independent ready task before waiting for an unrelated running task or plan. Waiting is valid only when nothing useful is ready: state the wait reason once and do not re-check or remind on unchanged facts.

**Scope and credential boundary:** each task brief carries the **inherited plan scope** (plan id + absolute `SDD dir` / brief / report / diff paths) — a leaf never selects or prepares a plan, writes the workflow snapshot / root register / shared indexes, or releases leases. Session JSON, `mstar plan --session` write credentials, and `--expect <revision>` stay with the PM/coordinator and are **never** handed to an implementer or reviewer (`mstar-iteration/references/plan-scoped-pm.md` §8).

**Dependent-task readiness:** review approval alone does not make a prerequisite available. PM serially integrates the reviewed prerequisite commits, then creates or updates the idle dependent worktree from that integrated state before recording its `BASE_SHA` and dispatching. For each required reviewed commit, record `git -C "$FEATURE_CWD" merge-base --is-ancestor <prerequisite-sha> <BASE_SHA>` with exit 0; a missing commit blocks only that dependent task. Do not move an active task's base; independent ready tasks continue concurrently.

## Per-task loop (PM only · Workflow)

1. Record `BASE_SHA` (never use `HEAD~1` later)
2. `mstar sdd workspace <plan-id>` → `SDD_DIR`（iteration L1 从 feature cwd 调用时：`MSTAR_CONTROL_ROOT=<main-repo-root>`（= **Git 派生的主 worktree 根**；先完成派生验证，fail-closed 守卫在其后）或 `mstar sdd workspace <plan-id> <main-repo-root>`；显式值必须与派生主根 canonicalize 一致，integration/外来检出被拒而非静默重定向；probe 以 v2 根 `status.json`（`workflows[]`）或 workflow snapshot 存在为准，linked worktree 缺文件会 fail closed）
3. `mstar sdd task-brief <plan> N` → brief file
4. Dispatch implementer:
    - Copy the plan task's budget into the Assignment header field **`Task budget (implement / ops rounds)`** (canonical template → `mstar-roles/references/project-manager/dispatch-and-assignment.md`; one-round capacity criterion → `mstar-artifacts/references/plan-quality-bar.md` item 7) — header region only, before the body markers
    - **`SDD implementer session: fresh`** (default) — new subagent; templates: `references/implementer-prompt.md`
    - **`SDD implementer session: sticky`** — first task: same as fresh + write `{SDD_DIR}/implementer-session.json` with `host_agent_id`; later tasks: host **resume** + `references/implementer-continuation-prompt.md` (see **`references/sticky-implementer-session.md`**)
5. On `DONE`: `mstar sdd review-package BASE HEAD` → diff file
6. Dispatch **fresh** task reviewer — role **`code-reviewer`** (L2; **not** `qc-specialist*`; host fallback generic + C5b → `mstar-host` C5) — brief, implementer report, diff, Global Constraints, and the reviewer's own output **`REPORT_FILE`** = `{SDD_DIR}/task-N-review.md` — `references/task-reviewer-prompt.md` — **never** sticky resume for reviewers
7. Fix loop for Critical/Important; re-review until approved. Then PM reads `{SDD_DIR}/task-N-review.md` — the always-on L2 report, never the implementer's `task-N-report.md` — before appending step 8: the earned `Task quality` and partial findings stand for the reviewed scope, but assigned review scope left uncovered blocks task-complete and dependent release, so PM routes the remaining scope through a fresh/tightened reviewer dispatch; it never overwrites an `Approved` earned for checked scope or invents `Needs fixes` because the budget ended
8. Append `progress.md`; record ledger progress through the **domain call** (`mstar plan progress --session <session.json> --file <absolute-json-path> --expect <revision>` on the scoped route; direct snapshot edit only on a non-scoped legacy route where the CLI is absent) plus `implementer-session.json` `last_task` if sticky — snapshot/revision semantics → `mstar-artifacts` `references/status-and-residuals.md`; scoped route → `mstar-iteration/references/plan-scoped-pm.md` §4/§7
9. Release dependent tasks only after reviewed prerequisite commits are present in their assigned base, per Dependent-task readiness above; independent ready tasks need not wait

**Never** dispatch parallel writers without isolated worktrees and disjoint ownership. Merge their outputs serially before producing the plan review-package.

Detail: **`references/file-handoffs.md`**.

> **Engine check (when available):** run `mstar sdd workspace <plan-id>` / `mstar sdd task-brief <plan-file> <task-number>` / `mstar sdd review-package <base> <head>` (or `import { assertBaseSha, sddWorkspace, taskBrief, reviewPackage } from "@mstar-harness/engine"` in a host hook) to drive the loop steps above. On `fail` -> do not proceed; fix and re-run. Skill text below remains authoritative when the runtime is absent.

## Implementer statuses

| Status | PM action |
|--------|-----------|
| DONE | review-package → task reviewer |
| DONE_WITH_CONCERNS | read concerns; fix scope issues before review |
| NEEDS_CONTEXT | provide context; re-dispatch. Budget overrun (the declared round cannot close its Files and gates) → split the task per `mstar-artifacts/references/plan-quality-bar.md` item 7 and re-dispatch with a fresh budget |
| BLOCKED | more context, split task, or escalate human — **never** same-model blind retry. Budget overrun → split the task per `mstar-artifacts/references/plan-quality-bar.md` item 7 and re-dispatch with a fresh budget |

## Reviewer ⚠️ items

`⚠️ Cannot verify from diff` does not block other findings. PM must resolve each before task complete.

## After all tasks

1. `mstar sdd review-package MERGE_BASE HEAD` → branch diff in `{SDD_DIR}/review/`
2. PM dispatches **plan QC tri-review (L3)** — **`QC mode: full tri-review`**, **N=3** — with branch review-package path and report paths under `{SDD_DIR}/review/` → **`mstar-review-qc`** · **`mstar-dispatch-gates`**. Layer SSOT → **`mstar-review-qc/references/review-responsibility-boundaries.md`**. PM writes `{SDD_DIR}/review/qc-consolidated.md` and durable main-plan gate summary. **Mandatory whenever `Execution mode: sdd`** (single-plan or iteration).
3. Critical/Important QC findings → fix assignments partitioned by ownership/dependency, then targeted re-review. Independent fixes run concurrently; PM retains the complete findings ledger. Fix rounds run on four mechanics — the per-task fix loop applies the same (`references/file-handoffs.md`):
    - **Unverified rounds count**: a fix round without verification evidence (reviewer not confirmed / report not on disk) is **not clean** — re-check and count the round; never enter the convergence branch.
    - **Complete ledger, scoped dispatch**: PM retains every open finding, including unverified items; each fix assignment carries only its owned findings and relevant fix delta. Unrelated findings do not expand a leaf task.
    - **Capped cross-round excerpt**: from round ≥2, the fix dispatch attaches only relevant prior findings and dispositions (advisory caps: ~500 words per round, ~1500 total — suggested values, not hard limits).
    - **Honest non-convergence**: open findings at wave close → list them in detail and state the disposition — re-feed to the next fix round **or** transfer to residual tracking — never silently close.
4. QA gate → **`mstar-harness-core`** Done rules; PM **`mstar-roles/references/project-manager/qa-trigger-matrix.md`**

> **On dsh:** the plan QC tri MAY run through the native **`workflow`** tool instead of three `subagent` dispatches — take the `script` + `meta` (`meta.name: mstar-qc-tri`) from skill **`mstar-host`** → `references/dsh-workflow-scripts.md` (§ `mstar-qc-tri`); the three seats stay read-only and PM persists `{SDD_DIR}/review/qc1.md`…`qc3.md` from their returned envelopes. Independent ready implementers use background **`subagent`** dispatches with isolated writable tracks — the `workflow` channel is read-only fan-out only; when the tool is unmounted (`ptc` preset) dispatch the three seats as background `subagent` calls (skill **`mstar-host`** → `references/dsh.md`).

## Progress ledger（Evidence）

PM at start: `cat {SDD_DIR}/progress.md`. Tasks marked complete are DONE — do not re-dispatch after compaction.

PM appends on clean review: `Task N: complete (<base>..<head>, review clean, review: task-N-review.md)` — the entry names the L2 report path the review closed on.

Minor findings → `## Minor (for plan QC)` section in same file.

> **Engine check (when available):** import `readProgressLedger` from `@mstar-harness/engine` in a host hook to read the ledger above (no CLI form yet). On `fail` -> do not proceed; fix and re-run. Skill text below remains authoritative when the runtime is absent.

## Red flags (NEVER)

- Parallel implementers sharing a worktree, ownership, or session
- Paste plan, diffs, or task history into dispatch prompts
- Dispatch reviewer without diff file
- `HEAD~1` as review BASE
- Pre-judge reviewer ("do not flag", "at most Minor")
- Skip task review or accept missing verdict
- Accept the L2 verdict from the message alone, or write L2 output to the implementer's `task-N-report.md` (the report is `{SDD_DIR}/task-N-review.md`)
- Mark a task complete or release dependents while the assigned L2 review scope is uncovered
- Re-dispatch tasks listed complete in ledger
- PM thread implements instead of subagent dispatch
- Sticky **resume** for task reviewers
- Resume implementer without `host_agent_id` in `implementer-session.json`

## CLI

The SDD helpers are engine-backed commands under **`mstar sdd`**（引擎 CLI；原 bash 脚本已移除，行为语义不变）。Run the `mstar` binary from any checkout; env vars `MSTAR_CONTROL_ROOT` / `MSTAR_HARNESS_DIR` / `SDD_DIR` are honored exactly as before.

| Command | Usage |
|--------|--------|
| `mstar sdd workspace` | `PLAN_ID [CONTROL_ROOT]` → creates `{SDD_DIR}` under control harness when set (`MSTAR_CONTROL_ROOT` or 2nd arg); fail closed on linked worktree without `status.json` |
| `mstar sdd task-brief` | `PLAN_FILE TASK_N [OUTFILE]` |
| `mstar sdd review-package` | `BASE HEAD [OUTFILE]` |

Developer check evidence: `mstar sdd evidence capture|verify` — capture runs an already-authorized argv once and retains raw evidence; verify is read-only. Command shapes, exit meanings and role boundaries → **`references/file-handoffs.md`** § Verification evidence. `mstar sdd exec` stays PM-only.

## References

- `references/file-handoffs.md` — paths and fix-loop evidence
- `references/sticky-implementer-session.md` — `fresh` vs `sticky`, ledger, host resume, micro-batch fallback
- `references/implementer-prompt.md`
- `references/implementer-continuation-prompt.md`
- `references/task-reviewer-prompt.md`
- `mstar-artifacts/references/plan-quality-bar.md` — plan self-containment standard (plans must meet this before SDD dispatch)